1. Field of the Invention
The invention relates to a backlight apparatus and, more particularly, to a backlight apparatus, without additional capacitors, capable of short prevention and voltage feedback compensation by means of changing the connecting pattern of a balance transformer circuit.
2. Description of the Prior Art
With the development of ever-enlarging size of Liquid Crystal Display (LCD) panel recently, a backlight apparatus with multiple Cold Cathode Fluorescent Lamps (CCFLs) has been broadly applied as a high quality optical source for LCD panel.
Please refer to FIG. 1. FIG. 1 is a schematic diagram illustrating a backlight apparatus of prior art with a balance circuit capable of short prevention and voltage feedback compensation. As shown in FIG. 1, the backlight apparatus 1, which is installed on a double-sided printed circuit board (PCB), treats multiple capacitors and resistors as voltage dividers on a secondary side of the balance circuit of a balance transformer 14. A voltage of node A in FIG. 1 is measured and compared to a default value for judging whether the balance circuit is short or not. In addition, at the node B in FIG. 1, a kick-off voltage is measured for adjusting voltage provided by a power source 10, so as to achieve voltage feedback compensation.
In the aforesaid balance circuit, a lot of capacitors and resistors are needed to achieve short prevention and voltage feedback compensation. However, the additional components are increasing the complexity of circuit and the cost of product. Besides, because that the capacitors used in the double-sided PCB are not adapted to the single-sided PCB. Therefore, a backlight apparatus on single-sided PCB is unable to achieve the short prevention and voltage feedback compensation by the prior art.
The invention discloses a backlight apparatus, without additional capacitors, capable of short prevention and voltage feedback compensation by means of changing the connecting pattern of a balance transformer circuit, so as to solve the aforesaid problems.